The overall objectives of our research are: (1) to determine how the constraints that are imposed by the human speech production and perception systems account for the classes of speech sounds that are utilized universally in language, and (2) to study and to account for the characteristics of speech sounds when they occur in sentences, and to specify strategies that are employed by speakers in producing these sounds in sentences and by listeners in decoding this acoustic representation. Proposed work includes further specification of the behavior of the larynx during speech production, description of quantal articulatory and acoustic attributes for certain places of articulation for consonants and vowels, experimental work leading to further delineation of the property-detecting capabilities of the auditory system that play a role in the perception of consonants, physiological studies of the mechanisms whereby speech movements are controlled, and specification of some of the rules used by a speaker in timing certain vowel and consonant sequences in sentences, together with the perceptual relevance of these timing rules. Bibliographic references: Klatt, D.H., Vowel Lengthening is Syntactically Determined in a Connected Discourse, Journal of Phonetics 3, pp. 161-172. (1975); Stevens, K.N. and Klatt, D.H., Current Models of Sound Sources for Speech. In B. Wyke (Ed.) Ventilatory and Phonatory Control Systems London: Oxford University Press, pp. 279-292 (1974).